Reaction jet housing for marine propulsion system

ABSTRACT

A marine reaction jet drive having a waterflow passageway including inlet and outlet openings, a propulsion means in the passageway intermediate the inlet and outlet openings, and conduit means separate from the passageway affording communication between the outlet opening or any suitable fluid pressure source and the inlet openings to provide a scavenging waterflow, characterized by a plurality of hollow perforated tubular bars being arranged to provide the inlet openings of the drive in the form of a screen having a series of spaced parallel slots between the inlet openings and the conduit means being connected with the bars to obtain a scavenging injection through the perforations of the bars.

States Patent [1 1 [1-11 3,8WA92 'llaitaeda et al. May '7, W74

[54] REACTION JET HOUSING FOR MARINE 3,527,430 9/l9 7O Smith 60/3909 P PROPULSION SYSTEM 3,588,266 6/1971 Scott et al 4l5/53 [75] Inventors: Hisanobu Takaeda, Fukunari; FOREIGN PATENTS R APPLICATIONS Atsushi Satomoto, Toyota, both of 850,261 10/1960 Great Britain 415/ 121 G Japan 73 Assignee: 1 115111 Seiki Kabushiki Kaisha, Aichi Raduaz" Pref Japan Attorney, Agent, or Fzrm--Oblon, Fisher, Sp1val,

' M Cl 11 d 22 Filed: Aug. 31, 1972 c e [21] Appl. No.: 285,375 [57] ABSTRACT i A marine reaction. jet drive having a waterflow pas- Foreign Application Pri it D t sageway including inlet and outlet openings, a propul- Sept. 12 1971 Japan 46-70614 means the passageway intermediate the inlet and outlet openings, and conduit means separate from 52 U S CL u G, P 10/4 the passageway affording communication between the 415/147 outlet opening or any suitable fluid pressure source 51 1m. 01 F0ld 15/00 BOld 29/38 and the inlet Pe11ings Pmide a scavenging Water- [58] Field of Search 415/12i o 53 147- I Characterized by plurality Perfmled 60/3909 210/411 tubular bars being arranged to provide the inlet open- I ings of the drive in the form of a screen having a series 56] References Cited of spaced parallel slots between the inlet openings and the conduit means being connected with the bars to UNITED STATES PATENTS obtain a scavenging injection through the perforations 2,834,534 5/l958 Kadosch et al. 415/53 of the bars. 3,306,046 2/1967 Trapp /0.5 3,367,1 l6 2/1968 5 Claims, 9 Drawing Figures Stallmann .1 115/o.5

PATENTEBMM 7 1914 3.809 492 SHEET20F3 REACTION JET HOUSING FOR NE PROPULSION SYSTEM BACKGROUND OF THE INVENTION 1. Field Of The Invention This invention relates generally to marine propulsion systems and more particularly to marine reaction jet propulsion drives.

2. Description Of The Prior Art In jet propelled boats, screening devices are usually provided at the inlet openings to prevent debris or the like from entering into the water passageways thereof, and during the travel of the boat, a collection of such debris and the like is apt to be produced on the screening device at the inlet openings in the bottom of the boat. Such collection of debris or the like obviously operates undesirably to decrease the propulsive efficiency of the boat. I

While various means have been previously employed for preventing the collection of debris or the like at the inlet openings of marine, propulsion drives, none have proven to the'entirely satisfactory.

SUMMARY OF THE INVENTION A principal object of the present invention therefore is to provide amarine reaction jet drive having improved means for preventing the collection of debris or the like 'at the inlet openings thereof.

The foregoing object and others are attained according to at least one aspect of the present invention through the provision of a scavenging flow of water at the inlet openings of a marine reaction jet drive.

Thus, in the disclosed embodiments, a plurality of hollow tubular perforated bars are provided to fabricate the inlet openings in the form of a screen having the inlet openings therein, and conduit means terminating at the ends of the bars are placed in communication with any suitable fluid pressure source, or with the discharge of the reaction jet housing outlet when the drive is operating under the conditions of forward drive. A valve means is further interposed in the conduit means, between the fluid pressure source or the outlet and the end of each of the bars, so as to intercept or allow the flow of water either manually or in response to a pres sure differential between the passageway and the discharge. I

BRIEF DESCRIPTION OF THE DRAWING Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the accompanying drawings, wherein like reference numerals are used throughout to designate FIG. is a fragmentary view similar to FIG. 1 of another embodiment of the present invention;

FIGS. 6 and 7 are both sectional views taken along the line VI-VI of FIG. 8 showing details of the valve means of the embodiment of FIG. 5;

FIG. 8 is a sectional view taken along the line VIII- -VIII of FIG. 7; and

FIG. 9 is a partially cut off view of the embodiment of FIG. 5, as viewed from the left side of F IG. 8, along the line lX-IX.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Referring now to the drawings, and more particularly to FIG. 1 thereof, the marine propulsion system of the present invention comprises an inboard reaction jet drive I and an engine, not shown, both mounted on a boat hull 3. An output shaft 4 of the engine is connected through an appropriate coupling device 5 and a gear reduction device 6 to the input shaft 7 of the jet drive 1. The reaction jet drive 1 comprises, in addition to the shaft 7, a housing 8, and means in the form of bolts 9 for mounting the housing 8 to the boat hull 3, defining a waterflow passageway 10. The waterflow passageway 10 has inlet openings 11 formed by a plurality of hollow tubular bars 20 arranged in parallel at the entrance of the passageway in the bottom of the boat hull 3, as shown in FIG. 2, and an outlet opening 12 at a transom 13 of the boat hull 3. Water is displaced through the waterflow passageway 10 by'a propellor drive 14 disposed therein and fixed to the shaft 7. A duct I5 is mounted by means of bolts 16 on the outlet portion of the housing 8. The duct 15 is concentrically aligned with the waterflow passageway 10 to complete the passageway, and the desired direction of the discharged waterflow is ensured by the duct.

Carried by radialarms 18 is a bearing 17 at the central position of the duct 15-for rotatably supporting an outer end of the driving shaft 7, such arms 18 providing therebetween radialslots through which water. can freely flow.

One of the significant characteristics of the present invention is the plurality of hollow tubular bars 20 provided for preventing debris and the like from entering the passageway 10, in which the inlet openings 11 are fabricated in the form of a screen S having a series of spaced parallel slots or openings 11, as shown in the plan view of FIG. 2. Debris and the like are of course prevented from entering the passageway '10 by this screen S. Further, each of the bars 20 is provided with perforations 30 in its underside wall so that a scavenging or cleaning jet can be obtained through the perforations as hereinbelow will be described in detail.

Thus, in order to prevent collection of debris at the openings 11 when the boat hull 3 is being forwardly propelled, means are provided for scavenging or cleaning any such debris by flowing or discharging to the openings 11 a part of the discharge from the outlet opening 12 while the propellor drive 14 is in its forwardly propelling position. This part of the discharge is received in a conduit 19 and directed to conduits 31 past the valve means 22 and in turn to each bar 20. The conduit 19 includes a bended end 21 disposed in the internal surface of the duct 15 in communication with the internal space of the duct 15. When the fluid pres sure within the space is larger than that of the internal space of each of the hollow bars 20, a part of the water flow travels through the conduit 19 and is directed to each bar 20, through the valve 22, and in turn through 3 each conduit 31. The valve means is normally closed but opens under a condition in which a pressure differential is produced between the outside and inside of the passageway 10, as hereinb'elow will be described in detail. 9

As shown in FIGS. 3 and 4, a piston 23 is slidable within a bore 24 formed in the wall of the housing 8 and is normally spring biased by a spring 26 toward abutment against an adjustable screw 25. A space 28 defined by the pistonand the bore communicates with the passageway by way of a conduit 27. A screw 29 is shown in FIG. 1 at the end of bended conduit portion .21, being provided for the sake'of mere design or working convenience to close the conduit thereof.

During the forward travel of the boat, the collection of debris and the like D is apt to be produced by the suction of the drive 1, on the screen S, as shown in FIG. Such collection interrupts the suction flow of the water so that fluid pressure within the passageway 10 is decreased as compared to that outside of the passageway. A pressure differential is thus effected between the space 28 and the conduit 19 so that the piston 23 is displaced upwardly as seen in FIG. 4 against the spring 26. The valve means 22 is accordingly opened'to allow flow'of water toward the bars 20. Since the fluid pressure at the discharge of the outlet opening 12 is always kept higher, in operation, than that at inlet openings 11, flow of water toward the bars 20 is effected past the valve means 22. As a result, the desired scavenger flow of water is obtained through the perforations 30 in the underside wall of the bars 20, as shown by the arrows in FIG. 4.

In FIGS. 5 to 9, there is shown another embodiment of the present inven'tion,'which embodiment is almost identical in construction to the first embodiment shown in FIGS. 1 to 4 except that the valve means 22' is so constructed as to be manually operated.

Since the-construction and operation of the similar parts of the second embodiment are readily understood by those skilled in the art, no description of this construction and the operation is necessary. Description only of the valve means 22' will however be made hereinbelow.

A hollow tubular valve 40 rotatably fits in an aperture 24 in the bottom wall of the housing 8 as shown in FIG. 6. The valve 40 protrudes outwardly to the left in FIG. 8 beyond the left outside face of the housing 8, being provided within its wall with a plurality of aligned holes 41 corresponding in number to the conduits 31. It will be noted that the space 42 within the valve 40 is communicated to or intercepted from the conduits 31 and in turn the tubular bars 20 by manually rotating the valve 40. The valve 40 is connected at its left end, as seen in FIG. 8, in watertight relation with a nipple 43, which is in turn connected to a flexible pipe 44 communicating with a fluid pressure source P. The nipple 43 has at its right end a flange in slidable contact with the face of the housing 8, which is further slidably supported by a generally ring-shaped supporter 46 mounted on the housing 8 by means of bolts 47, as shown in section in FIG 8. A seal ring 49 serves to hold the space 42 watertight relative to the outside of the valve 40.

The nipple 43 carries an arm 48 fast thereon, as best shown in FIG. 9. A link 50 is connected at its end to the arm 48 so that the arm 48 may be swung about the axis of the valve 40 by pulling the link 50 to the right, in the view of FIG. 9, for opening the valve. Whenever the oper'ator becomes aware of the collection of debris from a decrease of speed of travel of the boat, he may pull the link 50 so that the valve 40 is opened to allow flow of water from a pressure fluid source P to each bar past the valve 40 and conduits 31. Water injections are thus obtained through each perforation 30 to scavenge the collection of the debris on the screen S.

The link 50 may be connected to any suitable operating means, such as a lever or handle, not shown, which will be within convenient reach of the operator. Such operating means will be provided with an end stopper anda restoring spring, as may readily be designed by those skilled in the art, so that the valve is normally spring-biased toward closure of the valve 40 until the handle or the lever abuts the stopper. Since the above implement for pulling the link 50 and its operation is well understood, no illustration is necessary to those skilled in the art.

The pipe 44 may beconnected to the pressure fluid source as previously described and as shown in FIG. 5

by the reference character P and the dotted line. However, the pipe 44 also may be connected to the discharge at the outlet opening 12 of the drive 1 so that the scavenging jet is obtained in the same way as that of the first embodiment.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is to be understood, therefore, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A reaction jet housing comprising:

means defining a water flow passageway including an inlet opening and an outlet opening;

a propulsion means in said passageway intermediate said inlet opening and said outlet opening;

screen means in said inlet opening being formed of a.

plurality of hollow tubular perforated bars, whereby said inlet openings are fabricated in the form of a screen having a series of spaced parallel openings;

conduit means for supplying pressurized water flow to each of said bars; and

valve means for controlling said pressurized water flow to said bars including an aperture formed in a wall of said housing and a piston slidable in said aperture being normally spring biased toward a closed position, while opposed faces thereof are exposed to fluid pressures within said passageway and said conduit means respectively,

the discharge at said outlet opening and each of said bars being interconnected by said conduit means through said valve means to control the water flow therethrough.

2. A reaction jet housing as set forth in claim 1, wherein said bars are arranged to fabricate the inlet openings in the form of a screen having a series of spaced and parallel slot-shaped inlet openings of a size to safely prevent debris from entering said passageway.

3. A reaction jet housing comprising: means defining a water flow passageway including at least one inlet opening and an outlet opening;

water propulsion means disposed in said passageway between said at least one inlet opening and said outlet opening;

screen means in said at least one inlet opening for preventing debris and the like from entering said passageway;

means for supplying pressurized water flow to said screen means from within said passageway to clean said screen means of debris and the like collected thereon; and

means responsive to a pressure differential between said passageway and said outlet opening for controlling the pressurized water flow supplying means to automatically either permit or prevent the supply thereof to said screen means.

4. A reaction jet housing comprising:

means defining a water flow passageway including an inlet opening and an outlet opening;

a propulsion means in said passageway intermediate said inlet opening and said outlet opening;

screen means in'said inlet opening being formed of a plurality of hollow tubular perforated bars,

whereby said inlet openings are fabricated in the form of a screen having a series of spaced parallel openings;

conduit means for supplying pressurized water flow to each of said bars; and

valve means for controlling said pressurized water flow to said bars including a perforated hollow tubular member, an aperture in a wall of said housing in which said tubular member rotatably fits, conduit means to conduct pressurized water flow into said tubular member, and a plurality of conduit means corresponding in number to said perforations of said hollow tubular member as well as to said bars to connect said tubular member with said bars.

5 A reaction jet housing as set forth in claim 4, wherein said bars are arranged to fabricate said inlet opening in the form of a screen having a series of spaced and parallel slot-shaped inlet openings of a size to safely prevent debris from entering the passageway. 

1. A reaction jet housing comprising: means defining a water flow passageway including an inlet opening and an outlet opening; a propulsion means in said passageway intermediate said inlet opening and said outlet opening; screen means in said inlet opening being formed of a plurality of hollow tubular perforated bars, whereby said inlet openings are fabricated in the form of a screen having a series of spaced parallel openings; conduit means for supplying pressurized water flow to each of said bars; and valve means for controlling said pressurized water flow to said bars including an aperture formed in a wall of said housing and a piston slidable in said aperture being normally spring biased toward a closed position, while opposed faces thereof are exposed to fluid pressures within said passageway and said conduit means respectively, the discharge at said outlet opening and each of said bars being interconnected by said conduit means through said valve means to control the water flow therethrough.
 2. A reaction jet housing as set forth in claim 1, wherein said bars are arranged to fabricate the inlet openings in the form of a screen having a series of spaced and parallel slot-shaped inlet openings of a size to safely prevent debris from entering said passageway.
 3. A reaction jet housing comprising: means defining a water flow passageway including at least one inlet opening and an outlet opening; water propulsion means disposed in said passageway between said at least one inlet opening and said outlet opening; screen means in said at least one inlet opening for preventing debris and the like from entering said passageway; means for supplying pressurized water flow to said screen means from within said passageway to clean said screen means of debris and the like collected thereon; and means responsive to a pressure differential between said passageway and said outlet opening for controlling the pressurized water flow supplying means to automatically either permit or prevent the supply thereof to said screen means.
 4. A reaction jet housing comprising: means defining a water flow passageway including an inlet opening and an outlet opening; a propulsion means in said passageway intermediate said inlet opening and said outlet opening; screen means in said inlet opening being formed of a plurality of hollow tubular perforated bars, whereby said inlet openings are fabricated in the form of a screen having a series of spaced parallel openings; conduit means for supplying pressurized water flow to each of said bars; and valve means for controlling said pressurized water flow to said bars including a perforated hollow tubular member, an aperture in a wall of said housing in which said tubular member rotatably fits, conduit means to conduct pressurized water flow into said tubular member, and a plurality of conduit means Corresponding in number to said perforations of said hollow tubular member as well as to said bars to connect said tubular member with said bars.
 5. A reaction jet housing as set forth in claim 4, wherein said bars are arranged to fabricate said inlet opening in the form of a screen having a series of spaced and parallel slot-shaped inlet openings of a size to safely prevent debris from entering the passageway. 